fix(stm32mp1): add bl prefix for internal linker script

Due to patch [1], the bl prefix was removed from the build macros.
It should then add explicitly when compiling stm32mp1.ld.S.

[1] 434d0491c5 ("refactor(makefile): remove BL prefixes in build macros")

Change-Id: I298dba2a7c958dd4ea6429c83ed4b1ee97e1735f
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/plat/st/stm32mp1/platform.mk b/plat/st/stm32mp1/platform.mk
index 1c2c9f0..28463f1 100644
--- a/plat/st/stm32mp1/platform.mk
+++ b/plat/st/stm32mp1/platform.mk
@@ -323,7 +323,7 @@
 		-c plat/st/stm32mp1/stm32mp1.S -o $@
 endif
 
-$(eval $(call MAKE_LD,${STM32_TF_LINKERFILE},plat/st/stm32mp1/stm32mp1.ld.S,2))
+$(eval $(call MAKE_LD,${STM32_TF_LINKERFILE},plat/st/stm32mp1/stm32mp1.ld.S,bl2))
 
 tf-a-%.elf: stm32mp1-%.o ${STM32_TF_LINKERFILE}
 	@echo "  LDS     $<"